In recent years, sodium-ion batteries have emerged as a "newcomer" in the field of energy storage. They have the advantages of abundant raw material reserves, easy extraction, low cost, and independent control, and are expected to complement lithium-ion batteries in energy storage and other fields. In May this year, the country's first large-capacity sodium-ion battery energy storage power station was completed and put into operation in Guangxi, marking a key breakthrough in the large-scale energy storage engineering technology of sodium-ion batteries, and the large-scale application of sodium-ion batteries may enter the "fast lane".
Breakthrough in large-scale energy storage engineering technology
In Wuming District, Nanning City, Guangxi, the Fulin Sodium Ion Battery Energy Storage Power Station, which has just been put into use for a full month, is located in the green fields. Looking down from the air, the battery compartment, energy storage converter compartment, booster compartment, etc. form a white and green grid array. In the main control building of the power station, technicians can monitor the operation of the energy storage power station in real time through the electronic large screen. The total capacity of the battery, the health of the battery, the performance indicators of charging and discharging, as well as the real-time parameters such as frequency, voltage, and active power are clearly visible.
In recent years, with the continuous increase in the proportion of new energy installed capacity, new energy power generation methods such as wind power and photovoltaic power generation are intermittent, and the pressure of power peak regulation is increasing. The need to introduce new energy storage as a flexible regulation resource is very urgent. After the Fulin Sodium Ion Battery Energy Storage Power Station was put into operation, it effectively improved the power system's ability to absorb new energy.
Luo Chuansheng, senior engineer of the Nanning Power Supply Bureau of the Southern Power Grid, Guangxi, told reporters that the energy storage power station can complete a charge and discharge in 8 hours. It can participate in power peak regulation intelligently through the connected lines, realize flexible storage and release of new energy electricity, and play the role of "stabilizer" and "regulator" for the safe operation of the power grid.
Industry insiders said that although the working principle and production process of sodium-ion batteries are similar to those of lithium-ion batteries, and they have the advantages of high performance, high safety, long life, wide temperature range, and high power, many new problems still need to be overcome to apply sodium-ion battery technology to large-capacity energy storage power stations.
"The main technical challenges are battery technology, system integration and safety control." Gao Like, deputy general manager of the Innovation Management Department of the Guangxi Power Grid Company of the Southern Power Grid, said that first, breakthroughs should be made in the large-scale preparation of high-performance materials and battery cells, second, energy storage system integration technology that is fully suitable for the electrothermal characteristics of large-capacity sodium-ion batteries should be developed, and third, a complete set of fire prevention and control technology for large-capacity sodium-ion battery energy storage.
After technical research, the project team developed a sodium-ion energy storage battery with a capacity of 210 ampere-hours, long life, wide temperature range, and high safety, as well as the first domestic 10-megawatt-hour sodium-ion battery energy storage system, and applied it to the Fulin sodium-ion battery energy storage power station, forming a complete solution from "materials-battery cells-energy storage system-engineering construction". The project team has obtained a total of 26 invention patents, filling the gaps in sodium-ion battery materials, sodium-ion battery integration technology, and sodium-ion battery energy storage safety control technology.
Cost advantage has not yet emerged, and the upstream and downstream industrial chains need to be improved
Industry insiders believe that with the breakthrough of key technologies, sodium ion battery energy storage is expected to become the lowest-cost electrochemical energy storage technology, and its development prospects are promising. However, as a new energy storage technology, it still has a long way to go before it can be truly applied on a large scale.
The reporter learned that sodium-ion batteries and lithium-ion batteries are both rechargeable batteries discovered in the 1970s, but the early market demand was mainly concentrated in 3C products, which required high battery energy density. Lithium-ion batteries, which have more advantages in this regard, were the first to develop rapidly. Considering the sustainability and cost of resources, sodium-ion batteries have only regained widespread attention from academia and industry in recent years.
At present, the application of sodium-ion batteries in the field of energy storage still needs to benchmark lithium-ion batteries in terms of performance and cost to further improve technical and economic efficiency. At the performance level, the energy density of sodium-ion batteries is relatively low, and the technical maturity needs to be improved; at the cost level, with the downward trend of lithium prices, the comprehensive cost advantages of sodium-ion batteries need to be further explored.
"The current energy density of sodium-ion batteries is about 20% lower than that of lithium iron phosphate batteries. We must further increase research and development efforts to improve the energy density of sodium-ion batteries while ensuring safety performance, thereby reducing their manufacturing costs and system costs." Gao Like said that as the technology gradually matures, the energy density of sodium-ion batteries will increase rapidly, and it is expected to catch up with lithium-ion batteries within one to two years.
To give full play to the cost advantage of sodium-ion batteries, large-scale mass production is necessary. Li Jinghong, an academician of the Chinese Academy of Sciences and a professor at the Department of Chemistry at Tsinghua University, said that although the raw materials of sodium-ion batteries are abundant and the cost is low, the overall output is currently small, and the costs of supporting raw materials, manufacturing processes, and application technology are all high, resulting in its actual production cost being higher than that of current lithium-ion batteries.
Many interviewees said that although my country's sodium-ion batteries have achieved a certain leading position, they are still in the early stages of industrialization. Their technical route and market positioning are not clear, and market recognition and acceptance need to be improved. It will take some time to form an upstream and downstream industrial chain. However, for the industry, sodium-ion batteries and lithium-ion batteries are interchangeable in use, and can be manufactured on the same line as lithium-ion batteries, so the cost of industrial line conversion is relatively low.
Promoting high-quality development of the sodium-ion battery industry
Interviewees believe that the development of the new energy storage industry requires joint efforts and support from the government, enterprises and society. Comprehensive measures should be taken to coordinate innovation around difficulties, accelerate the innovation and application of new energy storage technologies such as sodium-ion battery energy storage, and provide strong support for promoting large-scale and high-proportion consumption of new energy, building a new power system and a new energy system, and promoting the realization of the "dual carbon" goal.
Li Zhen, deputy secretary-general of the Zhongguancun Energy Storage Industry Technology Alliance, suggested that the country needs to continue to focus on supporting key technical links such as positive and negative electrode materials, electrolytes, battery cell production, and battery integration in sodium-ion batteries. While maintaining my country's advanced sodium-ion battery technology, it is also necessary to provide support for different technical routes of sodium-ion batteries, promote demonstration applications of different scales and scenarios, accelerate the industrialization of technology, and promote integrated applications.
Promoting industrialization requires the establishment of a complete energy storage industry chain. In this regard, Gao Like suggested strengthening the coordinated development of sodium-ion battery energy storage companies with industries such as electricity, energy, and transportation, realizing the diversified application of energy storage technology, and reducing the cost of new energy storage technologies and improving economic efficiency through technological innovation and scale effects.
Li Jinghong believes that a sodium-ion battery energy storage industry cluster should be created to support upstream and downstream enterprises in the industrial chain to strengthen collaborative cooperation, promote the optimization and upgrading of the industrial chain, solve the cost problems caused by small scale and imperfect industrial chain, and improve the overall competitiveness of the industrial chain. At the same time, the connection between sodium-ion battery technology development and industrial application should be strengthened to solve the problems of disconnection between upstream and downstream applications of sodium-ion batteries and imperfect technical support.
At present, the sodium-ion battery industry is still in its early stages of development. For long-term development considerations, Li Zhen, Gao Like and others suggested formulating standards and quality specifications for new energy storage technologies such as sodium-ion batteries, establishing a product testing and certification system, promoting large-scale application in the downstream of the industrial chain, and promoting high-quality and standardized development of the industry. At the same time, guide power companies to carry out supervision and management of the entire life cycle of sodium-ion battery energy storage power stations. In addition, improve relevant laws and regulations, clarify the access standards, safety requirements and regulatory mechanisms for new energy storage technologies, and ensure the reliability and safety of sodium-ion battery energy storage technologies.